Sandra Carpenter is a London-based dancer who is distraught to learn that her friend has disappeared. Soon after the disappearance, she's approached by Harley Temple, a police investigator who believes her friend has been murdered by a serial killer who uses personal ads to find his victims. Temple hatches a plan to catch the killer using Sandra as bait, and Sandra agrees to help.
Dr. Paul Carruthers is frustrated because he thinks his employers, Mary Heath and Henry Morton, have cheated him out of the company's profits. He decides to get revenge by altering bats to grow twice their normal size and training them to attack when they smell a perfume of his own making. He mixes the perfume into a lotion, which he offers as a gift to Mary and Henry. When they turn up dead, a newspaper reporter decides to investigate.
Chuck Scott gets a job as chauffeur to tough guy Eddie Roman; but Chuck's involvement with Eddie's fearful wife becomes a nightmare.
